Partner Resource: item America, ESD: step-by-step explanation of protection areas (EPAs).
Content Type: Practical Implementation Guide.
Best For: Manufacturing operations managers and plant engineers responsible for assembly or handling of electronic components.

Who Should Read This

Read this if you are about to spec an electrostatic protected area (EPA), put a robot or conveyor inside one, or defend an existing one in a customer audit. The item guide explains the building blocks well. This debrief adds the numbers, the standard most US customers will ask about, and the risks that appear when people are no longer the only thing touching the parts.

Industry sectors: Electronics and PCB assembly, semiconductor back-end, industrial controls, automotive electronics, medical devices, and any line that handles bare boards, sensors, or ICs.

Job roles: Plant and manufacturing engineers who write the EPA spec. Automation engineers and integrators who bring robots, grippers, and conveyors into it. Quality leads who own compliance verification. Procurement teams who buy benches, flooring, and handling equipment.

Who else this concerns: Supply chain and customer service teams inherit the reputation damage when shipped components fail. Engineering spends time investigating field failures that already happened. Finance tracks warranty costs and replacement shipments.

What This Covers

The guide walks through an EPA from the door inward: access control and daily checks of protective equipment, dissipative flooring and its cleaning, workbench grounding, the rule that tools and containers within 30 cm of a sensitive part must be dissipative, ESD-safe chairs, and the hardest area, intralogistics. It references IEC 61340 and makes a point many buyers miss: ask the bench manufacturer for a measurement record at delivery, then keep measuring after installation.

That is a solid physical checklist. What it leaves to the reader is how to set the target: which parts you are protecting, which standard your customers will audit you against, and which limits go on the purchase order.

The RBTXpert Take

Start with Your Most Sensitive Part, Not the Room

The item guide notes that people only feel a discharge at around 3,000 V, while discharges as small as 30 V can damage components. Both figures are real, but the second one describes the most fragile parts on the market, not every part. Component makers rate ESD withstand voltage using two test models: human body model (HBM, per ANSI/ESDA/JEDEC JS-001) and charged device model (CDM, per JS-002). The lowest HBM classes look like this:

HBM Class	Withstand Voltage
0Z	< 50 V
0Z	50 V to < 125 V
0B	125 V to < 250 V
1A	250 V to < 500 V
1B	500 V to < 1,000 V

The US program standard, ANSI/ESD S20.20, is written to protect parts that withstand 100 V HBM, 200 V CDM, and 35 V on isolated conductors. The ESD Association (ESDA) states that if you handle class 0Z or 0A parts, the standard baseline is not enough: you need redundant controls and more frequent verification.

What to do: Before buying anything, pull the HBM and CDM ratings from the datasheets of the parts you handle and write down the lowest. That single number decides whether a standard EPA is sufficient or whether you are building a tighter one. A 30 V part and a 500 V part do not need the same room.

Name the Standard, Then Hold Every Vendor to it

item’s guide cites IEC 61340, the international series. In North America, customer audits and facility certifications usually reference ANSI/ESD S20.20 instead. The good news for buyers: the ESD Association’s technical forum has described the current IEC 61340-5-1 and S20.20 as technically equivalent. The differences are mainly in how insulators are measured and which document holds the verification test methods (ESD TR53 for S20.20, IEC 61340-5-4 for the IEC side).

Both standards require more than equipment. Each asks for a written ESD control program plan, a training plan, and a compliance verification plan. That is why EPA discipline is not a soft-skills add-on to the hardware. It is a clause an auditor will check.

What to do: Pick one standard, name it in your EPA spec and purchase orders for benches, flooring, footwear, and handling equipment, and ask each vendor for product qualification data measured to that standard’s test methods. If your customers audit to S20.20, IEC-qualified equipment will usually carry over, but confirm it rather than assume it.

Put Numbers in the Spec, not Adjectives

“Dissipative” and “ESD-safe” are not acceptance criteria. These are the ANSI/ESD S20.20 limits most EPA specs are built on:

Control Item	Required Limit	What happens if it fails
Wrist strap system (person to ground)	below 3.5 × 10^7 ohms	Replace strap or cord before the operator touches parts
Footwear and flooring system	below 1.0 × 10^9 ohms, and body voltage below 100 V	Operator must use a wrist strap instead
Process-required insulator within 12 in (30 cm) of a part	field of 2,000 V/in or less	Move it beyond 12 in, or neutralize with ionization
Process-required insulator within 1 in (2.5 cm) of a part	field of 125 V/in or less	Move it, or neutralize with ionization
Isolated conductor that cannot be grounded	below 35 V	Ground it, or redesign the fixture
Air ionizer offset (balance)	within ±35 V	Service or recalibrate the ionizer

Note how well item’s 30 cm rule for tools, holders, and containers lines up with the standard’s 12-inch insulator rule. The standard adds a second, tighter ring at 1 inch, which matters for fixtures, nests, and gripper fingers that touch the part directly. Non-essential insulators, such as coffee cups, food wrappers, and personal items, are simply banned from the EPA.

One rule the chair section should not obscure: item rightly recommends ergonomic, ESD-safe chairs. But under S20.20, a seated operator at an ESD workstation must still wear a grounded wrist strap, whatever the chair, flooring, or footwear. Chairs and footwear lose contact the moment someone lifts a foot. Plan either a documented daily wrist strap test or continuous monitors at seated stations, and never treat the chair as the ground path.

Automation Does Not Remove the ESD Risk. It Moves it

item is right that intralogistics is where EPAs get hard, because movement and friction are unavoidable. The same logic applies to robots, grippers, and feeders. It is tempting to assume that taking the operator out of the loop takes the ESD problem with them. The ESDA warns the opposite: components can be more sensitive to damage when assembled by automated equipment, for example when a part charges while sliding down a feeder and then discharges into a metal insertion head.

An ESDA standards working group on automated handling puts the shift plainly. Human body discharges are rarely the concern once people stop touching parts. The threats become charged-device discharges from the part itself, and discharges from isolated metal pieces of the machine. And because automated lines run fast, an uncontrolled charge source can damage thousands of parts before anyone notices.

When a robot, gripper, or conveyor enters your EPA, treat it as part of the ESD control program plan, with its own verification procedure. In practice:

Ground the machine, then prove the ground in motion. The working group recommends an equipment ground below 1 ohm. Parts that are grounded at the home position can lose that path while moving, so measure resistance to ground at the end effector across the working range, not only at rest. ESD SP10.1 gives procedures for this.
Treat gripper fingers as the tightest ring in the EPA. They sit inside the 1-inch zone by definition. Contact points should be dissipative. If fingers are printed or molded from plastic, check the material data sheet for a stated dissipative resistance range. If there is none, treat them as process-required insulators and measure the field they carry, or switch to a dissipative material such as an ESD-grade printing polymer.
Follow the cables. Dress packs and cable carriers flex and rub all day. A carrier built from ESD material only helps if conductivity runs continuously from one end to the other and the carrier is tied into ground. igus makes this point for its own ESD e-chain and triflex R robot dress packs, and the principle applies to any brand.
Measure the part, not only the machine. SP10.1 also covers checking whether the product itself picks up charge as it passes through the equipment. Do it at every handoff, such as feeder to gripper, gripper to fixture, and fixture to conveyor.
Plan for ionization where you cannot ground. Device packages are themselves insulators, and so are many fixture materials. Where they sit within 12 inches of the part and exceed the field limits, ionization is how S20.20 expects you to neutralize them.

Watch the Humidity, but do Not Lean on it

item mentions climate control only in passing, yet it changes how hard every other control has to work. ESDA reference data show the swing:

Activity	10 to 25% RH	65 to 95% RH
Walking across carpet	35,000 V	1,500 V
Walking across vinyl tile	12,000 V	250 V
Worker at bench	6,000 V	100 V
Polybag picked up from bench	20,000 V	1,200 V
Chair with urethane foam	18,000 V	1,500 V

The ESDA also stresses that charge still builds at high humidity. So humidity is a condition to log, not a control to rely on. Record relative humidity inside the EPA, and review verification results against it. A floor or strap that passes in a humid summer can be the weak link in a dry, heated winter.

Verification is the Program

An EPA takes as much organizational discipline to keep as hardware to build. The standards make that concrete. S20.20 requires a compliance verification plan and records that prove conformity. The ESDA advises setting check frequency by how heavily each item is used, how durable it is, and how much risk it carries.

A workable starting cadence looks like this:

Daily, or at every EPA entry: wrist strap and footwear checks, which matches item’s advice to check staff at least daily before they enter. Continuous monitors can replace the daily strap test.
Periodically, by risk: worksurfaces, flooring, carts, trolley roller elements and drag chains, ionizers, and each robot’s ground path in motion.
Whenever something changes: a new fixture, new gripper fingers, a relocated conveyor, or a new cleaning agent. item’s warning about cleaning agents is a good example of a change that can quietly break the dissipative path.

Why Field Returns Cannot Prove Your EPA Works

The opening scenario in item’s guide, a part that fails eight months after shipment, is the classic case for ESD control. It is worth knowing that the ESDA’s own glossary calls the concept of latent ESD failure controversial and not fully accepted. Latent damage is very hard to detect or prove after a part is assembled into a product.

That has a practical consequence. You cannot use a clean warranty record to prove that your EPA is working, and you cannot easily pin a field failure on ESD after the fact. Your evidence has to come from the process: the measurement records, the verification logs, and the resistance and field readings at every point where a part is touched.

Questions to Ask Any EPA Equipment Vendor

item sets a good bar by shipping its ESD workbenches with a measurement record for every ESD point. Use that as the baseline for every supplier, whether they sell benches, flooring, conveyors, robots, or grippers:

Which standard, and which test method, was this product qualified to? Can you share the measured values, not just the pass statement?
Will the delivered unit come with its own measurement record, and which points does it cover?
For anything that moves: was resistance to ground measured in motion, across the full range of travel?
Is the ESD property built into the material, or applied as a coating or topical antistat that can wear or wash off?
Which cleaning agents preserve the rating, and which void it?

The answers become the baseline readings for your own compliance verification plan. If a vendor cannot answer questions 1 and 3, you have nothing to verify against.

Final Notes

Three practical elements deserve consideration beyond what the guide covers.

First, EPA maintenance is ongoing and carries real cost. Dissipative flooring must be cleaned with specialist agents that preserve the dissipative properties. Regular measurement is required, not optional. Work chairs and transport equipment degrade and need replacement. These are not one-time purchases. If your organization treats ESD protection as a capital project rather than an operational discipline, the EPA fails slowly through neglect.

Second, EPA discipline enforces at the decision boundary. When a supplier pushes back on ESDS component handling, when production falls behind and someone suggests “just this once we skip the wristband,” when engineering wants to evaluate a component outside the EPA — these moments break the zone. Executive commitment matters more than flooring specs. The system is only as strong as your willingness to enforce it.

Third, EPA requirements create friction elsewhere in your operation. Integrating EPAs into intralogistics is harder than the article suggests. Conveyor systems, material handling, and transitions between protected and unprotected areas are where components escape safeguards. Plan for this complexity early. Build EPA boundaries into your facility layout before you design production flow around them.

Read the full item America guide on ESD protection zones here.
Check out item builds on RBTX.com here.